Buchon, N., Poidevin, M., Kwon, H.M., Guillou, A., Sottas, V., Lee, B.L., Lemaitre, B. (2009). A single modular serine protease integrates signals from pattern-recognition receptors upstream of the Drosophila Toll pathway.  Proc. Natl. Acad. Sci. U.S.A. 106(30): 12442--12447.

FBrf0208605

Research paper

The Drosophila Toll receptor does not interact directly with microbial determinants, but is instead activated by a cleaved form of the cytokine-like molecule Spätzle. During the immune response, Spätzle is processed by complex cascades of serine proteases, which are activated by secreted pattern-recognition receptors. Here, we demonstrate the essential role of ModSP, a modular serine protease, in the activation of the Toll pathway by gram-positive bacteria and fungi. Our analysis shows that ModSP integrates signals originating from the circulating recognition molecules GNBP3 and PGRP-SA and connects them to the Grass-SPE-Spätzle extracellular pathway upstream of the Toll receptor. It also reveals the conserved role of modular serine proteases in the activation of insect immune reactions.

PMC2718337 (PMC) (EuropePMC)